The main role of the relay

Relay is an automatic switching element with isolation function, which is widely used in remote control, telemetry, communication, automatic control, mechatronics and power electronic equipment, and is one of the most important control components.

Relays generally have induction mechanisms (input parts) that can reflect certain input variables (such as current, voltage, power, impedance, frequency, temperature, pressure, speed, light, etc.); There is an actuator (output part) that can realize "on" and "off" control of the controlled circuit; Between the input part and the output part of the relay, there is also an intermediate mechanism (drive part) for coupling isolation of the input quantity, functional processing and driving of the output part.

As a control element, in summary, the relay has the following functions:
(1) Expand the control range: for example, when the multi-contact relay control signal reaches a certain value, it can be exchanged, broken and turned on multiple circuits at the same time according to the different forms of the contact group.
(2) Amplification: For example, sensitive relays, intermediate relays, etc., with a very small amount of control, can control a very large power circuit.
(3) Comprehensive signal: For example, when multiple control signals are input into a multi-winding relay in the prescribed form, after comparative synthesis, a predetermined control effect is achieved.
(4) Automatic, remote control, monitoring: For example, the relay on the automatic device can form a program control line together with other electrical appliances, so as to realize automatic operation.